The 12 bit calibration value for both ADCs on both of my Xplain boards is the same number, 0x0ff. If I had a suspicious mind, I would be suspicious. :)
To be clear, that's CALH and CALL in the ADC. In the Production Signature Row, they are called ADCACAL0/1 and ADCBCAL0/1.
Everything else in the Production Signature Row seems less suspicious. Maybe they used a random number generator for those. :)